Conventionally, an electromagnetic shield pipe such as a metallic pipe or a composite pipe composed of a metallic layer and a resin layer is used as a protective pipe of a cable. Influence on the outside caused by noise that is generated from a cable inside or influence on the cable inside caused by noise on the outside can be suppressed by storing the cable in the electromagnetic shield pipe.
Herein, for example, in an automobile, in some cases, a plurality of cables such as a high-voltage electric wire for connecting a high-voltage battery and an inverter and a low-voltage electric wire for connecting a low-voltage battery and a relay box is stored in one electromagnetic shield pipe. In this case, generally, noise from the high-voltage electric wire is shielded so as not to be transmitted to the low-voltage electric wire in the interior of the electromagnetic shield pipe. As this specific example, an example in which the low-voltage electric wire is inserted into a shielding member (e.g., braided wire) is given.
In contrast, the high-voltage electric wire and the low-voltage electric wire that are exposed from the end portion of the electromagnetic shield pipe are respectively inserted into the shielding member (e.g., braided wire) so as not to come under the influence of noise. This shielding member is connected to the electromagnetic shield pipe in a conductive manner and constitutes an electromagnetic shield structure.
As this electromagnetic shield structure, for example, there is a method in which a braided wire into which the high-voltage electric wire is inserted and a braided wire into which the low-voltage electric wire is inserted are overlapped, and crimped with a crimp member such as a ring on a metallic portion (conductive portion) such as an end of an electromagnetic shield pipe (JP 2015-106466 A).
However, in the electromagnetic shield structure of Patent Document 1, on a connection portion between the braided wire and the electromagnetic shield pipe, there is an overlapping portion of the braided wire into which the high-voltage electric wire is inserted and the braided wire into which the low-voltage electric wire is inserted, and sections having a thickness different from the thickness of the overlapping portion occur on both sides of the overlapping portion. Thus, there are concerns about a holding strength of a crimping body might be reduced in a step of a thickness-varying portion of the braided wire which is the crimping body.
For example, holding strength on both sides of the overlapping portion of the braided wire is reduced due to heat cycle, repetitive bending, or tensile force, which might cause the shift or coming off of the braided wire, the coming off of the ring, and the like. Thus, there are concerns about stability regarding an energized state between the braided wire and the shield pipe or the holding strength of a crimp.
The present invention has been made in view of these problems, and it is an object of the present invention to provide an electromagnetic shield structure capable of securing a stable energizing state between a flexible shield member and an electromagnetic shield pipe and maintaining the holding strength of the flexible shield member for the long term.